A variety of wheat genetically engineered to emit a pheremone to ward off aphids “failed to show any effect” during a field trial in England, says Science Magazine. Researchers hoped the GE wheat would drive away the tiny pest, and save farmers from having to use chemical insecticides. An infestation of aphids can reduce wheat yields significantly. Scientists at Rothamsted Research designed a gene, based on one in peppermint plants, to mimic the chemical alarm released by aphids when they are attacked by one of their natural predators, a wasp.
Lab tests were encouraging – the wheat plants released the alarm pheremone, which warded off aphids and attracted the wasps. But there was no statistical difference between the number of aphids found on test plots of the GE wheat and conventional wheat in 2012 and 2013, says Science. Researchers say cool and wet summers may have depressed aphid populations, or that aphids eventually ignored the pheremone, which was emitted constantly by the GE wheat plants. One of the researchers says it likely will be several years before the team is ready with a new trial of GE wheat, this time engineered to emit the chemical alarm in pulses or only when the plant is attacked.